1. Field of the Invention.
This invention relates to fingerprint comparison apparatus and, in particular, to a system using recycling FIFO buffer memories to perform parallel processing of a correlation algorithm to determine an "electronic" match between a portion of a reference fingerprint and a live fingerprint.
2. Description of the Prior Art
Matching or comparing of fingerprints to assure a person's identity has been used and accepted for several decades. Apparatus which have been developed to date use minutiae methods, optical correlation and large computers with sophisticated software based programs to perform the comparison or identification. U.S. Pat. No. 4,246,568, discloses one device of which Applicants are aware that uses a minutiae method. U.S. Pat. No. 4,690,554 otherwise discloses a device that uses optical correlation.
Although some of these approaches have functioned to some degree, they are rather complex and expensive. They also lack in accuracy and robustness. That is, the minutiae method uses about 10 to 30 physical reference points within a fingerprint to determine a match, whereas the subject correlation method uses 1600 or more points, thus providing better accuracy. The simplicity of the correlation algorithm and hardware implementation result in a lower cost system. Robustness is achieved via an ability to obtain correct results even if several of the information pixels are missing or in error, due to the statistical nature of the algorithm.
Applicants are also aware of a serial software correlation approach, which can be found in a U.S. Air Force report, BMO TR-85-37, dated June 1, 1985. A software algorithm is disclosed therein which is implemented in an assembly language programmed general purpose computer. Although the system demonstrates relatively good Type II accuracy (i.e. rejection of the wrong person), the serial operation of the correlation algorithm produces a relatively slow throughput performance.
The FIFO based parallel pre-processor implementation of the present invention addresses the speed and cost deficiencies inherent in the foregoing software implementation. The resulting system can be used for credit/bank card validation, personnel access control, computer security and other similar applications.